Motor fuel containing a substituted asparagine

ABSTRACT

Motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing a minor amount of a substituted asparagine having the formula:   IN WHICH R and R&#39;&#39; each represent a secondary or tertiary alkyl or alkylene radical having from about seven to about 20 carbon atoms.

United States Patent Dorn et al. Nov. 20, 1973 [54] MOTOR FUELCONTAINING A 3,215,707 11/1965 Rense 44/71 X SUBSTITUTED ASPARAGINE [75]Inventors: Peter Dorn, Lagrangeville; Kenneth Primary ExaminerDaniel E.Wyman L. Dille, Wappingers Falls, both of Assistant Examiner-W. J. ShineN.Y. Attorney-Thomas H. Whaley et a]. [73] Assignee: Texaco Inc., NewYork, N.Y.

[22] Filed: Dec. 6, 1971 57 ABSTRACT [21] Appl' 205337 Motor fuelcomposition comprising a mixture of hy- Related US. Application Datadrocarbons in the gasoline boiling range containing a [63]Continuatiomimpan of No. 40,401, May 25, minor amount of a substitutedasparagine having the 1970, abandoned. formula:

H 521 US. Cl 44/71, 44/D1G. 1, 252/392,

260/534 R Hz CONHR [51] Int. Cl. C101 1/18, C101 1/22 [58] Field ofSearch 44/DIG. l, 71, 62;

252/392; 260/5 34 R in which R and R each represent a secondary ortertiary alkyl or alkylene radical having from about seven [56]References Clted to about 20 carbon atoms.

UNITED STATES PATENTS 5/1961 Andress et al. 44/71 11 Claims, No DrawingsMOTOR FUEL CONTAINING A-SUBSTITUTED ASPARAGINE This application is acontinuation-in-part of application Ser. No. 40,401, filed on May 25,1970, now abandoned.

BACKGROUND OF THE INVENTION l. Field of the Invention Modern internalcombustion engine design is undergoing important changes to meetstricter standards concerning engine and exhaust gas emissions. A majorchange in engine design recently adopted is the feeding of blow-by gasesfrom the crankcase zone of the engine into the intake air supply to thecarburetor just below the throttle plate, rather than venting thesegases to the atmosphere as in the past. The blow-by gases containsubstantial amounts of deposit-forming substances and are known to formdeposits in and around the throttle plate area of the carburetor. Thesedeposits restrict the flow of air through the carburetor at idle and atlow speeds so that an overrich fuel mixture results. This conditionproduces rough engine idling, stalling and also results in excessivehydrocarbon exhaust emissions to the atmosphere.

2. Description of the Prior Art US. Pat. No. 2,207,063 discloses the useof N(phydroxy-phenyl) dihydrocarbyl aspartate esters as gum inhibitorsfor hydrocarbon fuel oils.

US. Pat. No. 3,502,451 discloses motor fuel compositions containingpolymers and copolymers of C to C unsaturated hydrocarbons and thecorresponding hydrogenated polymers and copolymers having molecularweights ranging from about 500 to 3,500.

SUMMARY OF THE INVENTION A class of hydrocarbon substituted asparaginesare provided as carburetor detergents when employed in a liquidhydrocarbonaceous fuel for an internal combustion engine. Theseasparagines are characterized by having relatively long chain secondaryand tertiary hydrocarbyl radicals substituted on the nitrogen atoms inthe basic asparagine structure and appear to be unique in theirdetergency properties. The substituted asparagines in which the alkylradicals are secondary alkyl radicals surprisingly also possessanti-icing and corrosion inhibiting properties.

The fuel composition of the invention mitigates or overcomes theimportant problem of deposits laydown in the carburetor of an internalcombustion engine. When a gasoline of the invention is employed in acarburetor which has had a substantial build-up of deposits from prioroperations, a severe test of the detergency property of the fuel, thisgasoline is very effective for removing substantial amounts of thepreformed deposits.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substituted asparagineadditive of the invention is represented by the formula:

in which R and R each represent a secondary or tertiary alkyl oralkylene radical having from seven to carbon atomssln 2E6 preferredembodiment, R and R' represent the same or different secondary alkyl oralkylene radicals having from 12 to l8 carbon atoms.

There appears to be criticality in the structure of the substitutedasparagine particularly with respect to the hydrocarbyl radicalsrepresented by R and R. The asparagines having carburetor detergencyproperties are those in which R and R are secondary or-tertiaryhydrocarbyl or secondary or tertiary alkyl radicals. When R and R areprimary hydrocarbyl radicals, the compounds are generally too insolublein gasoline to be effective. When R and R are secondary hydrocarbylradicals, the compounds also possess carburetor anti-icing and corrosioninhibiting properties. While it is convenient for R and R to be the samehydrocarbyl radical it is sometimes advantageous for R and R to bedifferent hydrocarbyl groups or to be a mixture of secondary andtertiary hydrocarbyl radicals.

The additives of this invention have a number of advantages in additionto those noted above. The selected asparagines in gasoline are generallyresistant to the formation of insoluble calcium soaps, to the formationof lead precipitates in the presence of terne metal and to the formationof emulsions in the presence of water.

The substituted asparagines are prepared by the reaction of maleicanhydride with a suitable amine according to the following reactionsteps:

\ HC OH- RINH 0 ENE z H 2 H -GNHR HCO In general, a mole of a suitablesecondary or tertiary hydrocarbyl amine is reacted with maleic anhydrideat a moderate temperature preferably dissolved in-an organic solvent,such as benzene. Following the initial reaction step, the reactionmixture is cooled to a temperature of about 50C or below and anothermole of the hydrocarbyl amine is added to the reaction mixture. On thecompletion of this addition, the temperature of the reaction mixture israised to the reflux temperature of the solvent and the mixture refluxedfor an extended period until the reaction is complete. The yield of thesubstituted asparagine is substantially quantitative.

Examples of substituted asparagines which are effective in the presentinvention include:

N,N-di-C -C secondary alkyl asparagine N,N-di-C -C, secondary alkylasparagine N,N'-di-C, -C secondary alkyl asparagine N,N-di-C -Csecondary alkyl asparagine N-sec.-octyl,N'-sec. lauryl asparagineN-sec.-nonyl,N-sec. octadecyl asparagine N,N'-di-C, tertiary alkylasparagine N,N-di-C tertiary alkyl asparagine N-C sec. alkyl-N'-C,tertiary alkyl asparagine N-C tert. alkyl-N-C, tert. alkyl asparagineN,N'-di-C -C .,-sec. alkyl asparagine The fuel composition of thepresent invention comprises a mixture of hydrocarbons in the gasolineboiling range containing a minor amount of the substituted hydrocarbylasparagine. In general, the additive is employed in the fuel compositionat a concentration ranging from 0.0005 to 0.1 weight percent with thepreferred concentration range being from about 0.002 to 0.02 weightpercent. The motor fuel composition of the invention can containadditives conventionally employed in gasoline including anti-knockagents, corrosion inhibitors, anti-oxidants and upper cylinderlubricants. This fuel composition can also contain valve depositinhibitors such as disclosed in US. Pat. No. 3,502,451 and thisdisclosure is incorporated in the present invention.

The following example illustrates the method of preparing thesubstituted asparagines of this invention.

EXAMPLE I Analysis Found Cale. %N 5.5 5.2 TAN 9L2 l04 TBN I05 104 n,,20[.4785

Any gasoline suitable for a spark-ignited, internal combustion enginecan be used in the practice of this invention. In general, the base fuelwill consist ofa mixture of hydrocarbons in the gasoline boiling range,i.e., from about 75 to 450F. The hydrocarbon components can consist ofparaffinic, naphthenic, aromatic and olefinic hydrocarbons obtained bythermal or catalytic cracking or reforming of petroleum hydrocarbons.

This base fuel will generally have a Research Octane Number above 85 andpreferably above 90.

The substituted asparagine additive of the invention was tested for itseffectiveness as a carburetor Detergency Test. This test is run on aChevrolet V-8 engine mounted on a test stand using a modified fourbarrel carburetor. The two secondary barrels of the carburetor aresealed and the feed to each of the primary barrels arranged so that anadditive fuel can be run in one barrel and a base fuel run in the other.The primary carburetor barrels were also modified so that they hadremovable aluminum inserts in the throttle plate area in order thatdeposits formed on the inserts in this area would be convenientlyweighed.

in the procedure designed to determine the effectiveness of an additivefuel to remove preformed deposits in the carburetor, the engine is runfor a period of time usually 24 or 48 hours using the base fuel as thefeed to both barrels with engine blow-by circulated to the air inlet ofthe carburetor. The weight of the deposits on both sleeves is determinedand recorded. The engine is then cycled for 24 additional hours withbase fuel being fed to one barrel, additive fuel to the other and noblow-by to the carburetor air inlet. The inserts are then removed fromthe carburetor and weighed to determine the difference between theperformance of the additive and non-additive fuels in removing thepreformed deposits. After the aluminum inserts are cleaned, they arereplaced in the carburetor and the process repeated with the fuelsreversed in the carburetor to minimize differences in fuel distributionand barrel construction. The deposit weights in the two runs areaveraged and the effectiveness of the base fuel and of the additive fuelfor removing deposits expressed in percent.

The base fuel employed in the following examples was a premium gradegasoline having a Research Octane Number of about 100 and containing 3cc of tetraethyl lead per gallon. This gasoline consisted of about 25%aromatic hydrocarbons, 10% olefinic hydrocarbons and 65% paraffinichydrocarbons and boiled in the range from about 90F to 360F.

The carburetor detergency test results obtained from the basefuel andthe additive-containing fuels are set forth in the following Table. Theadditive-containing fuels contained the active detergent additive at aconcentration of 20'PTB (pounds per thousand barrels of fuel), aconcentration equal to about 0.01 weight percent.

TABLE I Chevrolet Carburetor Detergency Test Deposit Removal DepositDeposit Percent Run Build-up Removed effective ms l Base Fuel 32.0 ll.235 2 Base Fuel 20 PTB 28.5 26.6 93

N.N'-di-C -C,,sec. alkyl asparagine Built up with base fuel.

EXAMPLE II A Chevrolet Carburetor Detergency Test was conductedemploying a gasoline containing N,N'-di-C, tert. alkyl asparagine as thedetergent. The base fuel was similar to the base fuel employed in TableI above.

TABLE [I Chevrolet Carburetor Detergency Test Run Fuel Percent Effectivel Base Fuel 41 2 Base Fuel 30 PTB alkyl asparagine Conventionalnon-dispersant gasoline additives also present.

This example illustrates that substituted asparagines, in which thealkyl radicals are tertiary alkyl radicals, are highly effectivecarburetor detergents.

The action of the substituted asparagines as anti stalling, anti-icingadditives was evaluated in a Glass Tube Carburetor lcing Bench Testconsisting of a glass tube containing a simulated throttle plate so thatcooled moisture saturated air from an ice tower is drawn through thesimple glass tube gasoline carburetor by suction from a vacuum pump. Thegasoline sample is placed on a sample bottle and is drawn into the glasscarburetor through a hypodermic needle which is usually 20 gauge.Evaporation of the gasoline in the glass tube further cools the coldmoist air with resulting ice formation on the simulated throttle plate.The formation of ice on the throttle plate causes a pressuredifferential which is registered on a manometer. The fuels were rated interms of seconds required to attain a pressure differential of 0.9 inchof mercury. Since most fuels stall in an engine in l to 4 minutes, 300seconds is the maximum time taken for a run. A recording of 300 secondsdenotes no simulated stall (pressure differential did not reach 0.9 inchof mercury), within the test period. Each fuel is run three times insuccession and the average is reported. If the differences in runs aregreat the glass tube carburetor and test throttle are TABLE Ill ANTI-1CING TEST The rust inhibitng properties of fuel compositions containingsecondary alkyl derivatives of the invention was determined in theColonial Pipeline Rust Test. This test is a modification of ASTM RustTest D-665-6O Procedure A. In the Colonial Pipeline Rust Test, a steelspindle is polished with non-waterproof fine emery cloth. The spindle isimmersed in a mixture containing 300 cc fuel and 30 cc distilled waterand is rotated at [F for 3.5 hours. The spindle is then rated visuallyto determine the amount of rust formation. A passing result is anaverage of less than rust.

The results of this test are set forth in Table IV below. The additiveswere employed at a concentration of pounds per thousand barrels of fuel.

TABLE IV Colonial Pipeline Rust Test Fuel Composition Percent Rust alkylasparagine trace. 5 5. N,N'-di-C,,-C, ,-sec. alkyl asparagine 5. 0 6.N.N-di-C,-C,-sec. alkyl asparagine 0, 0 7. N.N-di-C ,-tert. alkylasparagine lOO, 8. N,N-did-C, -C,,-tert. alkyl asparagine 80, 80

The foregoing test demonstrates the outstanding effectiveness ofsecondary alkyl derivatives of the invention in their rust inhibitingproperties in contrast to related materials which are ineffective inthese properties.

We claim:

1. A motor fuel composition comprising a mixture of hydrocarbons in thegasoline boiling range containing from about 0.0005 to 0.1 weightpercent of a substituted asparagine having the formula:

in which R and R each represent a secondary or a tertiary alkyl oralkylene radical having from about seven to 20 carbon atoms.

2. A motor fuel composition according to claim 1 in which R and Rrepresent secondary hydrocarbyl radicals.

3. A motor fuel composition according to claim 1 in which R and Rrepresent tertiary hydrocarbyl radicals.

4. A motor fuel composition according to claim 1 in which R and Rrepresent mixed secondary and tertiary hydrocarbyl radicals.

5. A motor fuel composition according to claim 1 in which R and Rrepresent secondary alkyl radicals having from 12 to 18 carbon atoms.

6. A motor fuel composition according to claim 1 containing N,N-di-C -C-sec. alkyl asparagine.

7. A motor fuel composition according to claim 1 containing N,N-di-C -C-sec. alkyl asparagine.

8. A motor fuel composition according to claim 1 containing N ,N-di-C,-C -sec. alkyl asparagine.

9. A motor fuel composition according to claim 1 containing N,N-di-C -C-sec. alkyl asparagine.

10. A motor fuel composition according to claim 1 containing N,N'-di-C,-tert. alkyl asparagine.

11. A motor fuel composition according to claim 1 containing from about0.002 weight percent to 0.02

weight percent of said asparagine.

2. A motor fuel composition according to claim 1 in which R and R''represent secondary hydrocarbyl radicals.
 3. A motor fuel compositionaccording to claim 1 in which R and R'' represent tertiary hydrocarbylradicals.
 4. A motor fuel composition according to claim 1 in which Rand R'' represent mixed secondary and tertiary hydrocarbyl radicals. 5.A motor fuel composition according to claim 1 in which R and R''represent secondary alkyl radicals having from 12 to 18 carbon atoms. 6.A motor fuel composition according to claim 1 containing N,N''-di-C14-C15-sec. alkyl asparagine.
 7. A motor fuel compositionaccording to claim 1 containing N, N''-di-C7-C9-sec. alkyl asparagine.8. A motor fuel composition according to claim 1 containing N,N''-di-C15-C20-sec. alkyl asparagine.
 9. A motor fuel compositionaccording to claim 1 containing N, N''-di-C11-C14-sec. alkyl asparagine.10. A motor fuel composition according to claim 1 containing N,N''-di-C12-tert. alkyl asparagine.
 11. A motor fuel compositionaccording to claim 1 containing from about 0.002 weight percent to 0.02weight percent of said asparagine.